fix nil socks5 proxy case

[dogancanbakir]

Proposed changes

Closes #475

$ go run . -sa ""   

                       _ ___    
   ___  _______ __ __ (_) _/_ __
  / _ \/ __/ _ \\ \ // / _/ // /
 / .__/_/  \___/_\_\/_/_/ \_, / 
/_/                      /___/

                projectdiscovery.io

[INF] Current proxify version v0.0.12 (latest)
[INF] HTTP Proxy Listening on 127.0.0.1:8888
[INF] Saving proxify logs to proxify_logs.jsonl
- Ctrl+C pressed in Terminal

Checklist

• Pull request is created against the dev branch
• All checks passed (lint, unit/integration/regression tests etc.) with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

[Mzack9999]

If the intent is to suppress socks5 from listening (which happens by default), maybe we should consider reversing the logic and having an empty value by default which skip the socks5 initialization and enable it only with valid "[ip]:port" value. If left empty the OS will listen on arbitrary port on 0.0.0.0 which might be an unwanted behavior

[dogancanbakir]

If the -sa flag was set to an empty string (""), the program would exit because of this line return p.socks5proxy.ListenAndServe("tcp", p.options.ListenAddrSocks5) would no longer wait/listen to anything. However, we have modified the program to wait for all goroutines to finish. So, the intent is not to suppress socks5; instead, keep the program running even if socks5 is not specified.

[Mzack9999]

lgtm - I get your point. My observation was more related to potential usability improvement. Since we allow suppressing socks5, and have a flag to define it's behavior, maybe the following could look more intuitive?

flagSet.DynamicVar(&options.ListenAddrSocks5, "sa", "127.0.0.1:10080", "Listening SOCKS IP and Port address (ip:port)"),

Which will result in:

• proxify => no socks5 proxy
• proxify -sa => socks5 on 127.0.0.1:10080
• proxyfy -sa x.x.x.x:yy => socks5 on x.x.x.x:yy